21706738560 has 384 divisors, whose sum is σ = 83257826400. Its totient is φ = 5342478336.

The previous prime is 21706738531. The next prime is 21706738601. The reversal of 21706738560 is 6583760712.

21706738560 is a `hidden beast` number, since 2 + 17 + 0 + 6 + 73 + 8 + 560 = 666.

It is a tau number, because it is divible by the number of its divisors (384).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 2916604 + ... + 2924036.

Almost surely, 2^21706738560 is an apocalyptic number.

21706738560 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21706738560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41628913200).

21706738560 is an abundant number, since it is smaller than the sum of its proper divisors (61551087840).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21706738560 is a wasteful number, since it uses less digits than its factorization.

21706738560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7487 (or 7456 counting only the distinct ones).

The product of its (nonzero) digits is 423360, while the sum is 45.

The spelling of 21706738560 in words is "twenty-one billion, seven hundred six million, seven hundred thirty-eight thousand, five hundred sixty".